A clinical study coordinated by the French National Research Institute for Sustainable Development and Chiang Mai University with their Thai, American, and French partners, strengthens the case for a new strategy to prevent mother-to-child transmission of the hepatitis B virus.

Is the elimination of perinatal transmission in Thailand possible?

The results of this clinical trial, which was conducted in Thailand for 5 years, were published on March 8th 2018 in the New England Journal of Medicine.

In Western European countries and the United States, hepatitis B is an acute infection acquired during adulthood. Patients generally recover from it. However, in Asia, hepatitis B is most often acquired at birth or in early childhood and often becomes a chronic disease that can lead to cirrhosis and hepatic cancer in adulthood. Furthermore, hepatitis B affects over 100 million people in Asia and is a major public health problem.

In Thailand, over 2 million adults are infected with the virus, more than 5 times the number with HIV. Public authorities have already succeeded in eliminating mother-to-child transmission of HIV and syphilis and are now showing their willingness to eliminate perinatal transmission of the hepatitis B virus.

In this study, the international team led by Gonzague Jourdain (French National Research Institute for Sustainable Development), along with Thai, American, and French partners, sought to assess the effectiveness and tolerance of a new approach to preventing transmission of the hepatitis B virus among mothers with a high risk for transmission. In fact, because of their very high viral load, there is still a risk of these mothers transmitting the virus to their children despite administering vaccine and immunoglobulins to the newborn.

The scientific team became interested in the possibility of strengthening the current strategy (using a vaccine and immunoglobulins) by adding another element: giving the mother an antiviral (tenofovir disoproxil fumarate) once a day starting in the beginning of the third trimester of pregnancy until 2 months after birth. The team had a dual objective: to limit the number of children infected at birth as much as possible and to check how well women tolerated the treatment.

In total, 331 women participated in this trial and were randomly split into two groups. The first group received the new treatment and the second received a placebo that looked exactly the same. The results of the trial showed that none of the children in the group of women receiving the new treatment were infected by the virus. Moreover, the treatment was well tolerated by the mothers. In the placebo group, only 2% of children were infected, whereas previous studies, mostly conducted in China, reported more transmissions.

For Gonzague Jourdain, the French National Research Institute for Sustainable Development epidemiologist coordinating this study, these results "provide hope that we may be able to implement a simple, inexpensive strategy to help mothers with hepatitis B and high viral loads to limit the risk of transmitting the virus to their children, both in Asia and around the world".